Yeah I looked at the DT "poster board" a couple times (each time I was in there) thinking I would just get a sheet. Each time I wound up saying heck this is just a big sheet of cardstock. Wound up using a manila folder from a file cabinet instead. It's the same weight. But they have colors, if you want black or something, but the color's only on the surface, white shows on your edges.
...but it's just a dollar